[Comparison of the effects of removable dentures made by 3D printing and traditional casting methods on patients' subjective feelings].

PURPOSE: To compare the different effects of removable dentures made by 3D printing and traditional casting methods on patients' subjective feelings. METHODS: A total of 80 patients with dentition defects of Ken's Class Ⅰ and Subclass Ⅱ were selected from the Department of Prosthodontics. The patients were randomly divided into 2 groups, with removable dentures made by using 3D printing and plaster casting method, respectively. The patients were asked to re-visit 1 week after wearing the dentures to observe and record intraoral mucosal tenderness points. At the same time, mastication efficiency was measured by absorbance method. The patients were followed up for 2 months after wearing dentures, and questionnaires were issued to them to investigate subjective feelings and satisfaction. The subjective feelings of patients included masticatory ability, retention effect, convenience, comfort, speech function and facial appearance. Satisfaction evaluation included three aspects: treatment duration, cost and final outcome. Each aspect of evaluation used a 5-point system, with a minimum score of 1 and a maximum score of 5. The higher the score, the better the patient's subjective feelings or the higher the satisfaction. The data were statistically analyzed with SPSS 17.0 software package. RESULTS: The tender points in 3D printing group was less than the plaster casting group, while the chewing efficiency of 3D printing group was higher than the plaster casting group, the difference was statistically significant (P＜0.05). The difference of subjective feeling and satisfaction was also significant between the two groups(P＜0.05). CONCLUSIONS: 3D printing to make removable denture has certain advantages in improving the accuracy of removable denture and the comfort of patients.

[An evaluation of fiber reinforced composites veneer in anterior esthetic restoration].

PURPOSE: To explore the advantages of fiber reinforced composites veneer in repairing discolorated and defective anterior teeth. METHODS: Twenty porcelain veneers and 20 fiber reinforced composites veneers specimens of 2 cm long, 2 cm wide and 1 mm in thickness, with a longitudinal cross section of 45° incline were made. Another 40 fiber reinforced composites specimens of the same shape were used for comparison. After polishing and acid treatment of all the specimens according to clinical routine, resin cement was used for bonding the porcelain cover with resin veneers slope, and the conjunct specimens were soaked in 40 ℃ warm water for 24 h and drying; then the two groups of specimens were put were put on the pressure testing platform of the universal testing machine, with 1 mm/min testing pressure, and 1 cm2 square head was contacted on the surface of the bonding interface. Computer was used to record the fracture process of the two groups of specimens and the maximum compressive strength of bonding interface automatically. The compressive strength of the bonding interface under the same conditions was evaluated. SPSS 12.0 software package was used for statistical analysis. RESULTS: The compressive strength of the bonding interface between fiber reinforced composites was significantly higher than that between porcelain and fiber reinforced composites(P<0.05). CONCLUSIONS: Compared with porcelain veneers that can not be repaired when damaged in the anterior teeth, high-strength fiber resin veneers can partially be repaired with the same material, which has obvious advantages.

[3-D reconstruction of the maxillary central incisor by digital camera].

PURPOSE: To evaluate the role of digital camera in reconstruction of 3-D solid model of the maxillary central incisor. METHODS: Photographs of each section of the maxillary central incisor were taken with digital camera, then the 3-D model was reconstructed with photoshop software and 3DMAX software. RESULTS: The precise 3-D solid model of the maxillary central incisor was successfully reconstructed. CONCLUSIONS: 3-D reconstruction of the maxillary central incisor can be completely accomplished by dentists themselves.

[Characteristics of free Ca2+ distribution in cultured osteoclast-like cells].

OBJECTIVE: To study the spatial distribution of free Ca2+ in osteoclast-like cells cultured on glass. METHODS: To detect the free Ca2+ in osteoclast-like cells, the images were analyzed with image software, using the laser scanning confocal microscope and fluorescent probe. RESULTS: At 37 degrees C the free Ca2+ in osteoclast-like cells could be labelled effectively with 10 micromol/L Fluo-3/AM, the intensity of Ca2+ fluorescent signal in the central part was greater than that in the peripheral part and in the same section the signal was not distributed evenly. CONCLUSION: The intensity of Ca2+ fluorescent signal is different among various organellae in osteoclast-like cell, which suggests the osteoclast-like cell modulate its own function through the spatial difference of free Ca2+ concentration.

[Clinical evaluation of masticatory function of implant supported dentures in partially edentulous patients].

OBJECTIVE: To evaluate the masticatory efficiency of implant supported dentures in partially edentulous patients and the patients' satisfaction on masticatory function. METHODS: The masticatory efficiency of implant supported dentures of 22 patients were tested. The questionnaire of the patients' satisfaction about masticatory function had also been collected. The correlativity of the masticatory efficiency of implant supported dentures and the scores evaluated by patients on masticatory function were analyzed. RESULTS: There were no differences in masticatory efficiency between implant supported denture and non-implant supported denture (natural teeth and porcelain-fused-to-metal fixed bridges). The patients gave high scores to the satisfaction about masticatory function in the questionnaire. But the test results of masticatory efficiency were not related with the scores evaluated by patients. CONCLUSION: The implant supported denture could meet the requirement of normal masticatory function. The patients were satisfactory with the masticatory function of implant supported dentures, but the patients' subjective evaluation about masticatory function was probably influenced by varied factors.

[Observation of osteoclasts on the root surface during human deciduous teeth resorption].

OBJECTIVE: To observe osteoclasts on the resorbing surface of human deciduous teeth. METHODS: After fixing the collected deciduous teeth, we prepared the tooth slices without decalcification, treated them with HE and TRAP dyestuff, and observed the osteoclasts under light and scanning electron microscope. RESULTS: There were large quantity of various forms of overlapping and huge osteoclasts with many nuclei and silk-like protuberances on the resorbing surface of deciduous teeth. The multinucleated osteoclasts align on the surface of coarse dentin. CONCLUSION: On the resorbing surface of human deciduous teeth there are large amount of osteoclasts which can be used as a source of studying human osteoclast.

[Investigation of the expression of calcitonin receptor mRNA in human osteoclasts on deciduous teeth].

OBJECTIVE: To investigate the expression of calcitonin receptor mRNA in the osteoclasts of the resorbing deciduous teeth. METHODS: After fixing the collected deciduous teeth, toluidine blue was performed and tartrate-resistant acid phosphatase (TRAP) staining was used to identify the osteoclasts on the resorbing surface of human deciduous teeth and in situ hybridization of calcitonin receptor mRNA to show its existence. RESULTS: There were a number of TRAP positive osteoclasts on the root surface which showed the expression of calcitonin receptor mRNA. CONCLUSION: On the resorbing surface of human deciduous teeth there are osteoclasts that express calcitonin receptor mRNA, so it is feasible to use this kind of osteoclast to test the effect of external factors on the expression of CTR mRNA.